apt-pkg/tagfile.h

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: tagfile.h,v 1.20 2003/05/19 17:13:57 doogie Exp $
   4 /* ######################################################################
   5
   6    Fast scanner for RFC-822 type header information
   7
   8    This parser handles Debian package files (and others). Their form is
   9    RFC-822 type header fields in groups separated by a blank line.
  10
  11    The parser reads the file and provides methods to step linearly
  12    over it or to jump to a pre-recorded start point and read that record.
  13
  14    A second class is used to perform pre-parsing of the record. It works
  15    by indexing the start of each header field and providing lookup
  16    functions for header fields.
  17
  18    ##################################################################### */
  19                                                                         /*}}}*/
  20 #ifndef PKGLIB_TAGFILE_H
  21 #define PKGLIB_TAGFILE_H
  22
  23
  24 #include <apt-pkg/fileutl.h>
  25 #include <stdio.h>
  26
  27 class pkgTagSection
  28 {
  29    const char *Section;
  30    const char *Stop;
  31
  32    // We have a limit of 256 tags per section.
  33    unsigned short Indexes[256];
  34    unsigned short AlphaIndexes[0x100];
  35
  36    unsigned int TagCount;
  37
  38    public:
  39
  40    inline bool operator ==(const pkgTagSection &rhs) {return Section == rhs.Section;};
  41    inline bool operator !=(const pkgTagSection &rhs) {return Section != rhs.Section;};
  42
  43    bool Find(const char *Tag,const char *&Start, const char *&End) const;
  44    bool Find(const char *Tag,unsigned &Pos) const;
  45    string FindS(const char *Tag) const;
  46    signed int FindI(const char *Tag,signed long Default = 0) const ;
  47    bool FindFlag(const char *Tag,unsigned long &Flags,
  48                  unsigned long Flag) const;
  49    bool Scan(const char *Start,unsigned long MaxLength);
  50    inline unsigned long size() const {return Stop - Section;};
  51    void Trim();
  52
  53    inline unsigned int Count() const {return TagCount;};
  54    inline void Get(const char *&Start,const char *&Stop,unsigned int I) const
  55                    {Start = Section + Indexes[I]; Stop = Section + Indexes[I+1];}
  56
  57    inline void GetSection(const char *&Start,const char *&Stop) const
  58    {
  59       Start = Section;
  60       Stop = this->Stop;
  61    };
  62
  63    pkgTagSection() : Section(0), Stop(0) {};
  64 };
  65
  66 class pkgTagFile
  67 {
  68    FileFd &Fd;
  69    char *Buffer;
  70    char *Start;
  71    char *End;
  72    bool Done;
  73    unsigned long iOffset;
  74    unsigned long Size;
  75
  76    bool Fill();
  77    bool Resize();
  78
  79    public:
  80
  81    bool Step(pkgTagSection &Section);
  82    inline unsigned long Offset() {return iOffset;};
  83    bool Jump(pkgTagSection &Tag,unsigned long Offset);
  84
  85    pkgTagFile(FileFd *F,unsigned long Size = 32*1024);
  86    ~pkgTagFile();
  87 };
  88
  89 /* This is the list of things to rewrite. The rewriter
  90    goes through and changes or adds each of these headers
  91    to suit. A zero forces the header to be erased, an empty string
  92    causes the old value to be used. (rewrite rule ignored) */
  93 struct TFRewriteData
  94 {
  95    const char *Tag;
  96    const char *Rewrite;
  97    const char *NewTag;
  98 };
  99 extern const char **TFRewritePackageOrder;
 100 extern const char **TFRewriteSourceOrder;
 101
 102 bool TFRewrite(FILE *Output,pkgTagSection const &Tags,const char *Order[],
 103                TFRewriteData *Rewrite);
 104
 105 #endif